Heizaemon Kurogane's Links
Although Souma is his elder cousin, and from a branch family, he calls him "niisan" or occasionally "niisama". Heiza looks up to his cousin and respects him deeply. Although not consciously, he's growing up to be a lot like him.
His little cousin, though he is like a little brother to him. Since he's known him since birth, and Heiza being the heir, Souma has a naturally strong protective instinct towards him.
After some struggle with the Yakuza boss pursuing him relentlessly, he's somehow now his sugar baby?!
Heiza has come to realize that he cares about and likes Seijuro, and wants to make "that old and weak man" happy as he knows of all the hardships he's gone through. Their agreement evolved to them dating, though the daddy and baby dynamics are still very much in tact, albeit Heiza is gentler with him now.
A sweet young man who was once his sugar baby, now upgraded to his boyfriend. Seijuro cares deeply for Heiza and does his best to make him happy. Through his interactions with Heiza, he has grown from a spoiled young master to the respectful head of his family, learning how to be responsible and caring in his own way.
Much like his cousin, he thinks of him as a puppy, but also a potential romantic interest. He knows Daichi likes him, but he feels unable to return those feelings on the same scale. Still, he allows him to be in his life as a friend even after their rocky start.
While his interest started thanks to Heiza's physical similarity to his cousin, Daichi soon developed a crush once they got closer. He likes talking and hanging out with Heiza, but decided to not push for a relationship, giving the Kurogane the space Daichi thinks he wants.
Heiza doesn't like admitting that he likes his elder half brother, but still falls back onto his support and help the moment he reappeared in his life. The two get along rather well regardless of their personality clashes, as Goemon is able to handle Heizas anger outbursts pretty well and knows how to easily calm him down.
Heiza is his half brother. Although they spent a lot of time together as young kids, after some time the contact became scarce. He's rather fond of him and likes to hug and dote on him, even though he knows that it gets on Heiza's nerves.